The human body contains a great number of tubular vessels and conduits through which flow a variety of physiological fluids. These tubular vessels and conduits include the vascular system, the urological system, the intestinal system, as well as other body conduits. Flow through these conduits may be restricted by obstructions or other reductions in the flow passageway. For example, a vascular obstruction in the form of deposits or growths in a patient's artery or vein may restrict or stop blood flow to a certain portion of the patient's body. As a second example, an obstruction in the urethra due to an enlarged prostate may restrict the passage of fluids through the urethral canal. This may be particularly serious if such an obstruction occurs in a portion of the vascular system or other body conduit that supplies vital organs with blood or other necessary fluids. Obstructions, must therefore, be removed quickly while minimizing trauma, discomfort and other negative impacts on the patient.
A number of different therapies are available for the treatment and removal of obstructing material from a vessel or other body conduit. Notably, balloon angioplasty and mechanical atherectomy have evolved as the two principal surgical procedures for the treatment of obstructions within the vascular system.
Balloon angioplasty comprises a procedure wherein a deflated balloon is introduced, by means of a catheter, to the obstructed area within the vessel or other body conduit. The balloon is then inflated to open the lumen or passageway of the conduit. The inflated balloon tends to crush or compact the obstructing material against the conduit wall as well as to crack the obstructing material and dilate the conduit so as to increase the patency of the conduit.
While balloon angioplasty is quite successful in substantially opening the lumen within certain vessels and conduits, it does not remove the obstructing material. Since this obstructing material is not removed, there is a significant possibility that the conduit will become re-occluded or re-obstructed at the treated area within a relatively short period of time. This re-occlusion generally requires another treatment to reopen the lumen.
The balloon angioplasty procedure has several additional drawbacks which tend to further reduce its desirability. For instance, in the case of a severely occluded vessel, it may be difficult to position the deflated balloon so that it spans the occlusion without causing undue trauma to the surrounding vessels. In addition, the balloon angioplasty procedure is not satisfactory for treating calcified and hard occlusions, which are more difficult to crack and dilate. Similarly, balloon angioplasty is not satisfactory for treating eccentric occlusions since the balloon tends to simply stretch the healthy vascular tissue without compressing the occluding material.
In contrast to balloon angioplasty, atherectomy procedures are diverted toward the removal of obstructing material from within the body conduit. These treatment devices use a variety of means to remove the obstructing material. For example, rotating cutters, abraders and lasers may be used. The rotating cutters may be particularly useful in removing certain types of vascular obstructions. In particular, since vascular obstructions may have different compositions and shapes, a given removal or cutting element may not be suitable for the removal of a particular obstruction. Alternatively, if a patient has multiple obstructions within a vessel, a given removal element may be suitable for removing only one of the obstructions. The cutting, grinding and abrading devices also have a tendency to perforate the wall of the vessel or conduit. This is of particular concern in curved sections of the vessel or conduit.
Based on these considerations, it is apparent that the need remains for a surgical device which can effectively remove obstructing material from within a vessel, a urethral canal, or other body conduit without perforating or otherwise damaging the conduit. There is also a need for such a surgical device which may be used to remove differing obstructing material from within various body conduits, each having a different diameter, curvature, or other configuration. There is also a need for such a device which is simple to use and inexpensive to manufacture.